Prudence Journal of Environmental Science Research Vol. 1(2), pp. 5-11 November, 2013 http:// prudencejournals.org/pjesr/index.htm ©2013 Prudence Journals Full Length Research Paper The hydrodynamic of Dong River, Hutan Lipur Lata Jarum, Pahang, Malaysia Mohd Khairul Amri Kamarudin¹*, Mohd. Ekhwan Toriman¹, Pan Ia Lun², Nor Azlina Abdul Aziz¹ and Muhd. Barzani Gasim² ¹Environmental Research Institute of the East Coast (ESERI), University Sultan Zainal Abidin, 21300 Kuala Terengganu, Terengganu. Malaysia. ²School of Environmental and Natural Resource Sciences (PPSSSA), Faculty of Science and Technology, National University of Malaysia, Malaysia. *Corresponding author. E-mail: amri.ukm@gmail.com. Accepted 13 September, 2013 ABSTRACT The natural environment of Lata Jarum with its chilly cold water of waterfall is one of the local leisure spots in Raub, Pahang. The waterfall of Dong River is located within the virgin forest Benum Mountain (or in local name is Gunung Benum) - Hutan Lipur Lata Jarum. For the hydrology research, we have five sampling stations with four stations at the upstream and one at downstream. This research is carried out in order to study the hydrodynamic of Dong River. Observed data was carried on 16 to 17 November 2009. The results indicate that, the flow was ranged from 3.452 to 20.331m³/s while velocity of water was ranged from 0.128 up to 4.000m/s. The XP-SWMM modeling was used to study the hydrodynamic of the river. Simulation result showed that, the flow was ranged from 5.995 to 36.212 m³/s and the velocity was ranged from 3.46 to 9.32m/s. Through the study, we can predict; the high velocity of river water would lead to river flooding easily once rainfall has occurred due to several characteristics of the river such as fast river velocity, limited drainage capacity and hydraulic regime which found to be less tolerate with high volume of discharge. Key words: Hydrodynamic river, river simulation, XP-SWMM modeling, Dong River. INTRODUCTION Availability of sufficient and appropriate data describing the cascade or channel characteristics is very rare especially in developing countries like Malaysia. However, in many countries, mostly because of maintenance costs, the present trend is a diminution of in situ networks (Vorosmarty et al., 1999). Moreover, large regions in the world are still poorly gauged due to accessibility difficulties (Augusto et al., 2009). This situation will change by taking a long-term on going process in hydrological scientific research and with the effort of collaboration of governmental agencies and scientific research institutions. Lata Jarum is located within the virgin forest named Hutan Lipur Lata Jarum, Hulu Dong. It possesses a natural cascade system and the water intake at the upstream of the river has been diverted to supply the water for electric generating plant of TNB (Empangan Hidroelektik Mini Hulu Dong) but the generating plant had been stopped from operation many years ago. The undisturbed and uniqueness of environment of Lata Jarum also famous with the blooming of Bunga Pakma (Rafflesia) is suitable for eco-tourism and research based destination. But at the same time, it should be put into effort to conserve and protect it for local welfare. Erik (1978) and Gossling (2002) have found that, tourism contributes to our environmental changes especially to the physical environment. From a global perspective it contributes to changes in land cover and Prudence Prudence Prudence Prudence Journals Journals Journals Journals